This invention relates generally to an apparatus for controlling fluid flow, and more particularly, to a poppet valve.
Conventional poppet valve assemblies typically contain a housing, a solenoid coupled with the housing for generating an electromagnetic force, a magnetic armature within the housing that moves in response to the electromagnetic force, a stator that guides a push pin, a cone-shaped poppet, and a seat having an aperture. In operation, the solenoid moves the armature towards the stator, pushing the push pin towards the seat. The push pin is adjacent to the poppet, and pushes the poppet into the aperture of the seat, plugging it. The seat typically includes a poppet guide and has a channel for the flow of fluid through the seat and out of the poppet valve assembly when the aperture is not plugged by the poppet. The poppet is cone-shaped to ensure better alignment and fit with the aperture.
A pressurized fluid is applied to the aperture, and presses against the poppet when the aperture is plugged. If the force exerted by the fluid on the poppet exceeds the force exerted on the poppet by the armature and push pin, the poppet is forced away from the aperture, allowing for fluid flow through the aperture, the channel within the seat, and out of the poppet valve assembly. This typically decreases the pressure of the fluid. When the force exerted by the fluid on the poppet does not exceed the force exerted on the poppet by the armature and push pin, the poppet is pressed against the aperture, plugging it. Thus, by regulating the force with which the poppet presses against the aperture (by regulating the current through the solenoid), the pressure of the fluid may be controlled.
One problem with conventional poppet valve assemblies is that the pressure versus current (of the solenoid) graph is frequently less than ideal. FIG. 1a is a graph of desired pressure versus current for one type of conventional poppet valve assembly. Preferably, a map of pressure versus current will be a smooth, continuous curve or line. However, under certain operating conditions, such as high temperature and medium to high flow rates, the pressure versus current graph in many poppet valve assemblies has a discontinuity: a spike. FIG. 1b is a graph of actual pressure versus current for the one type of poppet valve assembly. At certain operating conditions, for a small increase in current, the pressure of the fluid increases disproportionally. This disproportional increase may cause a discontinuity with systems using the conventional poppet valve assembly, such as a fuel delivery system for an engine.
The present invention provides apparatuses for controlling fluid flow. A one-piece non-magnetic poppet of a first material is operable to be actuated from a first position to a second position. In the first position, the poppet plugs an aperture so as to resist fluid flow through the aperture, and in the second position the poppet is in a position that allows fluid flow through the aperture. The poppet may be coupled directly with an armature disposed within the housing.